<?php
/**
  * wechat php test
  */

//define your token
define("TOKEN", "ece44bfb7451c6c1abd33fabed0cc93d");
$wechatObj = new wechatCallbackapiTest();
$wechatObj->responseMsg();

class wechatCallbackapiTest
{
	public function valid()
    {
        $echoStr = $_GET["echostr"];

        //valid signature , option
        if($this->checkSignature()){
        	echo $echoStr;
        	exit;
        }
    }
    public function log($data){
        file_put_contents('data.log',$data,FILE_APPEND);
    }
    public function responseMsg()
    {
		//get post data, May be due to the different environments
		$postStr = $GLOBALS["HTTP_RAW_POST_DATA"];
        $this->log($postStr);
      	//extract post data
		if (!empty($postStr)){
                /* libxml_disable_entity_loader is to prevent XML eXternal Entity Injection,
                   the best way is to check the validity of xml by yourself */
                libxml_disable_entity_loader(true);
              	$postObj = simplexml_load_string($postStr, 'SimpleXMLElement', LIBXML_NOCDATA);
                $fromUsername = $postObj->FromUserName;
                $toUsername = $postObj->ToUserName;
                $type=$postObj->MsgType;
                $keyword = trim($postObj->Content);
                $time = time();
                $textTpl = "<xml>
							<ToUserName><![CDATA[%s]]></ToUserName>
							<FromUserName><![CDATA[%s]]></FromUserName>
							<CreateTime>%s</CreateTime>
							<MsgType><![CDATA[%s]]></MsgType>
							<Content><![CDATA[%s]]></Content>
							<FuncFlag>0</FuncFlag>
							</xml>"; 
                if( $type=='event' && $postObj->Event=='subscribe')
                {
                    $msgType = "text";
                    $contentStr = "欢迎关注!";
                    $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
                    echo $resultStr; 
                }              
				if( $keyword=='呆逼')
                {
              		$msgType = "text";
                	$contentStr = "你猜!";
                	$resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time, $msgType, $contentStr);
                	echo $resultStr;
                }
                if($keyword=="图文")
                {   
                    $artitle=array(array(
                        'Title'=>"百度",
                        'Description'=>'百度首页',
                        'PicUrl'=>'https://www.baidu.com/img/bd_logo1.png',
                        'Url'=>'https://www.baidu.com'
                        ),array(
                        'Title'=>"搜狗",
                        'Description'=>'搜狗首页',
                        'PicUrl'=>'https://www.sogou.com/images/logo/new/favicon.ico?v=2',
                        'Url'=>'https://www.sogou.com/'
                        )
                    );
                    $textTpl="<xml>
                        <ToUserName><![CDATA[%s]]></ToUserName>
                        <FromUserName><![CDATA[%s]]></FromUserName>
                        <CreateTime>%s</CreateTime>
                        <MsgType><![CDATA[news]]></MsgType>
                        <ArticleCount>%s</ArticleCount>
                        <Articles>";
                        foreach ($artitle as $a) {
                            $textTpl .="<item>
                            <Title><![CDATA[".$a['Title']."]]></Title> 
                            <Description><![CDATA[".$a['Description']."]]></Description>
                            <PicUrl><![CDATA[".$a['PicUrl']."]]></PicUrl>
                            <Url><![CDATA[".$a['Url']."]]></Url>
                            </item>";
                        };
                        $textTpl .="</Articles>
                        </xml>";
                    $resultStr = sprintf($textTpl, $fromUsername, $toUsername, $time,count($artitle));
                    echo $resultStr;
                }

        }else {
        	echo "";
        	exit;
        }
    }
		
	private function checkSignature()
	{
        // you must define TOKEN by yourself
        if (!defined("TOKEN")) {
            throw new Exception('TOKEN is not defined!');
        }
        
        $signature = $_GET["signature"];
        $timestamp = $_GET["timestamp"];
        $nonce = $_GET["nonce"];
        		
		$token = TOKEN;
		$tmpArr = array($token, $timestamp, $nonce);
        // use SORT_STRING rule
		sort($tmpArr, SORT_STRING);
		$tmpStr = implode( $tmpArr );
		$tmpStr = sha1( $tmpStr );
		
		if( $tmpStr == $signature ){
			return true;
		}else{
			return false;
		}
	}
}
?>
